Electric switch



{No Model.)

T. HARPER. ELECTRIC SWITCH.

No. 550,411. Patented Nov. 26, 1895;

W215 nawwex' W [72 we al 091- ANDREW B GRAHAM PHOTO-LITE) WASHKNGTONDCUNITED STATES PATENT OFFICE.

THOMAS HARPER, OF NEtV BRUNS\VICK, NE\V JERSEY.

ELECTRIC SWITCH.-

SPECIFICATION forming" part of Letters Patent NO; 550,411, datedNovember 26, 1895.

7 Application filed August 29, 1894. Serial No. 521,596. (No model.)

To aZZ whom it may concern:

Be it known that I, THOMAS HARPER, a citizen of the United States,residing at New Brunswick, Middlesex county, New Jersey, have inventedcertain new and useful Improvements in Electric Switches, of which thefollowing is a specification.

My invention relates to switches or devices for breaking and closingelectric circuits, and the object is in part to simplify and cheapen theconstruction and in part to obviate sparking when making or breakingcontact. The construction will be fully described hereinafter, and itsnovel features carefully defined in the claims.

It is very desirable in electric switches to prevent sparking when thecircuit is closed or broken, to thoroughly insulate the metalliccontact-surfaces when the circuit is broken, and to protect thecontact-surfaces at all times against oxidation from the action of theatmosphere, and my improvements permit of obtaining these desirableresults.

In the accompanying drawings 1 have shown several modes of carrying outmy invention and of adapting it to diiferent forms or kinds of switches.

Figures 1 and2 illustrate my invention embodied in a simple wall-switch,Fig. 1 being a section on line 1 1 in Fig. 2 and Fig. 2 a section online 2 2 in Fig. 1. Fig. 3 is a view similar to Fig. 1, showing theinvention applied to a double wall-switch. Fig. 4 illustrates theapplication of the invention to a double sliding switch. This viewrepresents the switch. partly in section and partly in plan. Figs. 5 and6 illustrate an embodiment of the invention in a knife switch, Fig. 5being a side elevation and Fig. 6 a section on line 6 6 in Fig. 5. Fig.7 illustrates amodifioation of the construction illustrated in Fig. 6.

Referring first to Figs. 1 and 2, wrepresents the basepiece or frame ofthe switch, in which is formed a cylindrical bore to receive a 1'0-tative carrier As here shown, this carrier has a knob at its outer end,whereby it may be rotated or turned axially in said bore by the thumband finger, and a cap-nut screwed on its inner end to prevent it frommoving longitudinally. The carrier 1 will be by preference made whollyof some insulating material; but it will suffice if the shank or journalthereof be made of such material. This shank fits snugly or closely inthe bore in the base-piece 00, and both the bore and shank may beslightly tapered.

a a represent the circuit-wires, terminating at the respectivebinding-posts b 11*, and 0 0* are the terminal contact-pieces of thecircuit. These pieces connect at one end with the respectivebinding-posts and at the other end enter the bore in the base-piece atopposite sides thereof. I11 the carrier or movable part y of the switchis mounted a contactpiece d, which extends diametrically through theshank thereof and has its extremities flush or even with the surface ofthe said shank, the extremities of the contact-pieces 0 e being alsoflush or even with the inner surface of the bore in the base-piece .93.

When the carrier or movable part y is so turned as to bring theextremities of the piece 61 into contact with those of the respectivestationary pieces 0 and 0 as seen in Fig. 1, the circuit will be closed,and when the movable part y is turned axially until the piece (Z is outof contact with the pieces 0 e as seen in Fig. 2, for example, thecircuit will be broken.

It is important that the surfaces of the stationary and movable parts ofthe switch shall be in close rubbing contact at all times, so that asthe face of the moving contact-piece passes off from that of thestationary contactpiece there will be no airspace or room for an arc toform, and consequently no spark; also, when the contactpieces separatein breaking the circuit the faces of the said pieces will be in closerubbing contact, the one with the material of the movable part y and theothers with the inner face of the bore in the stationary part a". Thiswill protect the contacting surfaces from oxidation and keep theminsulated.

The device as described is simple, easily constructed, and consequentlyinexpensive. Theform of the base-piece a: is not material. It may be ofsome known insulating material, as indurated fiber or the like, and behoused in an ornamental metal case x.

There maybe two or more circuits controlled by one such switch, as seenin Fi 3, which I denominate a double switch. In this construotion thereare two movable contactpieces cl in the shank of the carrier and twosets of contact-pieces 0 0 The carrier may be arranged to slide endwiseinstead of to rotate axially. This 0011- struction is illustrated inFig. 4, where y represents the sliding carrier bearing the movingcontact-pieces cl.

Figs. 5 and 6 illustrate the application of my invention. to aknife-switch. In these views 00 represents cheek-pieces on the base a),between which slide the knife or lever 3 which carries the movablecontact-piece (Z. The stationary contact-pieces c and 0 pass through thecheek-pieces 00 and are fixed therein. In Fig. 5 the full lines show thecircuit closed, the knife being depressed, and in Fig. 6 the circuit isrepresented as broken, the knife being elevated.

Fig. 7 illustrates a slight modification of the knife-switch, in whichone of the cheekpieces is omitted and the moving contactpiece d isconnected by a flexible coil 0 with the binding-post b My invention isadapted to all purposes where a simple circuit-closer and breaker isrequired, as in bell circuits, incandescent lights, &c.

I am aware that it is not new, in order to prevent sparking, to soconstruct an electrical circuit-breakin g device that at the instant ofbreaking the circuit insulating material is interposed between theterminals to break any are which may form, and this I do not claim.

Having thus described my invention, I claim-- 1. Aswitch comprising asocket of insulating material having on its inner surface two insulatedcontact-pieces adapted to form circuitterminals, and a carrierofinsulating material revolubly mounted in said socket with its surface incontact with the inner surface of the socket, said carrier being alsoprovided with two insulated contact-pieces electrically connected to oneanother and flush with the insulating material and in position tocontact with the respective contact pieces in the socket as the carrieris revolved, whereby, at the instant of breaking contact the insulatingmaterial adjacent to each terminal is interposed between the terminalsto break any are which may form, substantially as set forth.

2. A switch comprising a socket of insulating material having on itsinner surface two insulated contact-pieces adapted to formcircuit-terminals and a carrier of insulating material movably mountedin said socket with its surface in contact with the inner surface of thesocket, said carrier being also provided with a contact-piece arrangedto contact with the respective contact-pieces in the socket, theterminals being flush with the surfaces of the insulating material,whereby, at the instant of breaking contact the insulating materialadjacent to each terminal is interposed between the terminals to breakany are which may form, substantially, as set forth.

3. In a switch, the combination of a basepiece 00, having in it a bore,and a carrier 3 mounted rotatively and fitting snugly in said bore, ofinsulated contact-pieces c and 0 mounted in the wall about said borewith their extremities flush with the inner surface of said bore, andthe contact-piece d, mounted in and extending through the carrier y,with its extremities flush with the surface of the carrier and adaptedto be brought into contact with the pieces 0 and 0 by the axial rotationof the carrier, substantially as set forth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

THOMAS HARPER.

Witnesses 2 ROBERT S. TURTON, GRANVILLE L. MOORE.

